Stringed musical instrument



Oct. 3l, 1933- H; KuHRMEYr-:R

STRINGED MUSICAL INSTRUMENT Original Filed April '7, 1930 Patented ct.31, 1933 UNITED STATES PATENT OFFICE Application April 7, 1930, SerialNo. 442,123 Renewed March 2, 1933 25 Claims.

The present invention relates to improvements in stringed musicalinstruments, such, for example, as banjos, ukuleles, etc., and hasparticular reference to a new and improved mounting for the finger boardon the body.

In stringed musical instruments such as the foregoing, the strings aretensioned between a tail piece which is secured to one side of anannular body rim, and the free remote end of a neck which is attached toand extends radially from the rim at a point directly opposite the tailpiece. The top of the neck lies substantially in the plane of the upperperipheral edge of the rim, and is provided with a plurality of frets.The strings are normally maintained out of Contact with the neck andbody by means of a bridge supported on a head stretched across theperipheral edge of the rim. Each of the several strings accordinglydescribes two acute angles with the common plane of the neck and rim,with the apexes of these angles at the respective points of attachmentsof the ends of the strings to the instrument. The maximum permissibledivergence of the strings from the frets is practically limited by theextent to which the musician can readily depress any particular stringagainst the tensile effect produced as an incident to its being tuned.

The tension of the several strings introduces a compressive strain ofconsiderable magnitude in the neck and body of the instrument and thepresence of the bridge with the resulting angular relation between thestrings and the common plane of the neck and body produces anaccompanying bending moment whose tendency is to bow or arch the entireinstrument. Because of its relatively light construction, the bendingeffect is most pronounced in the neck and results in warping that memberin an arc whose degree of curvature reaches a maximum at the pointofattachment kof the strings and progressively diminishes toward the pointof attachment to the body. As a consequence, the separation of thestrings from the frets progressively increases as the instrument isused, and, due to arching tendency of the neck, reaches its.

greatest extent toward the point of attachment of the neck to the rim orbody. Eventually it becomes difficult to press the strings into contactwith the frets so as to utilize their intermediate lengths.

Heretofore it has been common practice to compensate for this inherentcharacteristic by pivotally adjusting `the neck about a point on theperipheral surface of the instrument body.

It will be apparent however that a relatively great pivoting movement ofthe extremity of the neck about its inner end Will be necessary in orderto correct the effect thusA produced. Pivoting the neck about a point onthe surface of the rim has, therefore, been an unsatisfactory expedientrequiring a wide degree of manipulation to produce a .corrective effect.

It is accordingly a primary object of the present invention toadjustably secure the neck of a stringed instrument to the body by meanswhich permits pivotal movementk of the neck about a point intermediateits respective ends thus causing a translating movement of the abuttingend relative to the plane of the rim.A

It is a further object of the invention to secure the neck to the rim bymeans adapted to distribute the compressive stresses produced by thestrings to a point in the periphery of the rim diametrically oppositethe point of attachment with the neck. y

Another` object is to provide means to effect adjustment of the neck andits restoration to rigid relation with respect to the rim which issimultaneously effective to communicate com pressive stresses to adiametrically opposed point in the rim.

Another object is to provide a construction such that the compressivestress induced by the tension of the strings is counteracted by aplurality of connected members which are effective to form a closedforce polygon.

A more specific` objectV is to provide an adjusting means for the neckof a stringed musical instrument which is simple, inexpensve, andcapable of easy and quick manipulation.

y In the accompanying drawing:

Figure 1 is a fragmental top elevation of a preferred form of theinvention as applied to a banjo.

Fig. 2 is a vertical sectional view taken line 3 3 of Fig. l.

Fig. 3 is a view similar to Fig. 2 but showing the neck in a differentposition of adjustment.

Fig, 4 is an enlarged detail sectional view.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawing and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed but intend to cover all modifications and f alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims.

Referring more particularly to the drawing, the

along y preferred embodiment of the invention is incorporated in a banjohaving a body or rim denning a peripheral edge 11 over which a head orskin (not shown) is adapted to be stretched. A neck 12 is secured to,and extends radially from, the external peripheral surface of the rim 10with its upper surface 13 substantially in the plane o1 the peripheraledge of the rim.

A plurality of strings (not shown) are adapted to be stretched between asuitable form of tail piece (not shown) which is anchored to the rimadjacent its peripheral edge 11, and a plurality of independent tuningpegs supported in the extremity of the neck 12. The strings aremaintained out of contact with the surfaces of the neck and head by abridge (not shown) which is supported upon and extends normally of thehead. A plurality of transverse slots 14 are formed in the upper surface13 of the neck 12 to receive suitable frets 15.

It is within the contemplation of the present invention to effectangular adjustment of the neck relative to the body and translation ofits inner end toward or from the plane of the upper peripheral edge ofthe body.

To this end, means is provided which affords a bearing surface ofsubstantially constant area between the body and the inner end of theneck for all angular positions of the latter, thereby insuring a rigidrelationship between the elements c! the instrument in any desiredposition of adjustment. In the present embodiment oi' the invention,auch means includes a concave arcuate seat 16 preferably formed in aplate 17 which is Secured to the external peripheral surface of the rim10 with the plane of its arcuate face submntially normal to the plane ofthe peripheral edge 11. The plate is retained in position by colmtersunkscrews 18 which engage the body of the rim.

The inner end 19 oi' the neck 12 is formed in a convex are whose planeis substantially normal to the piane oi the surface 13 and whose radiusis equal to the radius of the arc defining the seat 16. Thus the end 19of the neck 12 is adapted to be received in abutting contact with theseat 16 and me area of contact is substantially equal throughout thedesired range of adjustability of the neck. Translating movement of theend 19 of the neck Illlrelative to the seat 16 is preferably restrictedto a plane normal to the peripheral edge 11 of the rim 1li. `To thisend, guide means are provided which, in the present instance, comprisealined tongues 20 formed integrally with the plate 17 and adaptedtocoact with an elongated groove 21 which projects inwardly from theabutting and "19 of the neck.

l Concealed means is employed to attach the neck to the rim in fixedangular relation, and, in the embodiment of the invention selected forpurposes of disclosure, the attaching means is housed within the neck ofthe instrument and projects inwardly of the rim beneath the head orskin. The inner end of the neck is provided with a bore 22 which extendsinwardly from the abutting face 19 eccentrically o1' the longitudinalaxis or the neck.

`The attaching means comprises an elongated member 23 having an end 24anchored in the bore 22, the second end 25 projecting externally of ltheface 19 for engagement with the rim or body. Pivotal movement of theneck relative to the member 23 is provided by the anchored connection ofthe end 24 of the latter part in the bore 22. A pivot screw 26, isthreaded into the neck adjacent the inner end of the bore 22 andprojects through an aperture 27 formed near the end 24 of the member 23.The respective ends of the aperture 27 are flared as at 28 to permitangular movement of the member 23 about its end 24 in a plane common tothe axis of the pivot screw 26.

The protruding end 25 oi' the member 23 is threaded as at 29 and isadapted to project inwardly of the body of the instrument through alinedapertures 30 and 31 formed in the plate 17 and rim 10, respectively. Anadjustable nut 32 engages the threaded section 29 and acts against theinner peripheral surface of the rim to clamp the end 19 of the neck 12in abutting engagement with the seat 16 of the plate 17. A Washer 33 isinterposed between the nut 32 and the inner surface of the rim toprevent injury to the latter part.

Thus by manipulating the nut 32 the neck 12 may be adjusted angularlywith respect to the plane of the edge 11 by pivotal movement about anaxis intermediate its respective ends.

Spacing the pivotal axis of the neck away from the point of contact ofits inner end with the seat 16 lessens the extent of angular movementnecessary to effect any desired adjustment because the inner end isthereby caused to move toward the strings simultaneously with the actionof the remote end of the neck to converge the strings toward its uppersurface. Structural characteristics of the neck, however, limit thepractical depth of the bore and proportionally restrict the extent towhich the pivot point may be removed from its inner or abutting end, aswill be seen in Figs. 2 and 3.

Pivotal means have accordingly been provided in which the axis ofrotation is further removed from the abutting end of the neck than isthe point of connection between the respective elements of thestructure.

Referring now to Figs. 2 and 3: It will be seen that the alinedapertures 30 and 31 in plate 17 and rim 10 respectively, provide a snugt for the projecting end of member 23, thereby effecting a constantangular relationship between that part and the body. The bore 22,however, is substantlally greater in diameter than is the attach ingmember 23 permitting translation of the neck longitudinally of the axisof the pivot screw 26. Were the pivotal connection between the member 23and the neck incapable of translation axially of the screw 26 then theangular movement of the neck relative to the attaching member wouldoccur about an axis spaced from the abutting end of the neck a distanceequal to the distance of the axis of the pivot screw from the end of theneck. The actual axis of rotation, however, is removed a relativelygreater distance from the end 19 than is the screw 26 by causing themember 23 to translate with reference to the longitudinal axis of thescrew upon what is, in eiect, a cord of the angle whose apex defines theactual axis of rotation of the neck.

Thus, during an adjusting operation, t-he inne; end of the neck iscaused to move toward the strings a relatively greater amount than wouldbe possible were the axis of rotation no further from the abutting end19 than is the pivot screw 26.

The tension of the strings on the instrument i introduces a force actingdiametrically of the rim between the abutting end of the neck and thepoint of attachment of the strings, whose effect is to compress ordistort the body of the instrument, thereby destroying the adjustment 1of the head or skin and simultaneously reducing the tension of thestrings and lowering their tonal pitch.

Means is accordingly provided to exert a counteracting forcediametrically of the rim from the point of attachment of the necksubstantially to the point of attachment of the strings. It is furtherprovided that the counteracting force shall be exerted simultaneouslywith an operation to clamp the neck in adjusted position. The end 34 ofa brace 35 is adjustably secured in any suitable manner to the rim 1()at a point adjacent the point of attachment of the strings. The opposedend 36 of the brace 35 extends in juxtaposition to the inwardlyextending portion of the member 23. In the present instance the nut 32is adapted to engage threads 3'7 on the end 36 of the brace 35 tosimultaneously act upon the brace and the member 23. Referring to Figs.l and 4, it will be seen that clockwise rotation of the nut 32 willserve to draw the member 23 inwardly and simultaneously project the end36 of the brace 35 in the same direction to communicate a stress to theopposed side of the rim which is eiTective to compensate the strainintroduced by the strings.

It will be apparent that a comparatively sligh movement of the bracewill serve to relieve all compressive strain communicated to `the rim,whereas a relatively greater movement of the member 23 will be requiredto afford the degree of freedom necessary to readily adjust the neck ina desired angular position. This end has been attained in the presentinstance by providing the member 23 with threads whose pitch isappreciably greater than is the pitch of the threads 87 upon the brace35, as will be seen in Fig. 4.

Thus a pivotal connection has been provided for the neck o1 a stringedmusical instrument which is concealed from view, which is effective torotate vthe neck about an axis intermediate its ends, and which issimple and economical of construction. Adjustable brace means haslikewise been provided which is effective to communicate stressdiametrically of the rim to retain the latter part in properconformation and to compensate for the stress introduced by the tensionof the several strings.

claim as my invention:

1. A stringed musical instrument comprising, in combination, a rim, aplate rigidly secured to the external peripheral surface of said rim,said plate and rim defining radially alined concentric apertures, theouter face of said plate being curved in a concave arc Whose plane issubstantially perpendicular to the plane of said rim, a neck having aconvex arcuate end adapted to abut the arcuate face of said plate and alongitudinal bore extending inwardly therefrom, an elongated' memberuniversally anchored in said bore and projecting through said concentricapertures inwardly of said rim, a brace rod extending diametrically ofsaid rim substantially in the plane of the longitudinal axis of saidneck the end remote from said neck being secured to said rim, the secondend extending in juxtaposition to the inner end of said elongatedmember, and means adapted to communicate a compressive stress to saidbrace as anincident to exerting a tensile stress on said elongatedmember.

2. A stringed musical instrument comprising, in combination, a rimhaving an aperturetherein, a neck adapted to adjustably abut said rim inangular -relation to the plane of the edge thereof, said neck having abore extending inwardly from said abutting end, means providing asurface contact between said rim and the abutting end of said neck in aplurality of positions of angular adjustment, said means having anaperture concentric with the aperture in said rim, a member universallyanchored in said bore and projecting externally thereof, said memberbeing adapted to project inwardly of said rim through said concentricapertures, a brace extending diametrically of said rim substantially inthe plane of said neck, the end of said brace remote from said neckbeing secured to said rim, the second end of said brace extending injuxtaposition to the inner end of said member, and manually rotatablemeans connecting said member and the juxtaposed end of said brace toclamp said neck in fixed angular relation to said rim, andsimultaneously move said brace to communicate force to a point in saidrim diametrically opposite the point of attachment of said neck.

3. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck having one' end adapted to abut saidrim in angular relation to the plane of the edge thereof, said neckhaving a bore extending inwardly from said abutting end, coactingarcuate seats on said rim and the abutting end of said neck, saidarcuate seats having apertures concentric with the aperture in said rim,a member universally anchored in said bore and projecting externallythereof, said member being adapted to project inwardly of said rimthrough said concentric apertures, a brace extending diametrically ofsaid rim substantially in the plane of said neck, the end of said braceremote from said neck being secured to said rim, the second end of saidbrace extending in juxtaposition to the inner end of said member, andmanually operable means connecting said member and the juxtaposed end ofsaid brace to effect an inward radial movement of said member to clampsaid neck in fixed angular relation to said rim, and a relatively lessermovement of said brace to communicate force diametrically of said rim.

` 4. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck having one end adapted to adjustablyabut said rim in angular relation to the plane of the edge thereof, saidneck having a bore extending inwardly from said abutting end, coactingarcuate seats on said rim and the abutting end of said neck, saidarcuate seats having an aperture concentric with the aperture in saidrim, a member universally anchored in said bore and projectingexternally thereof, said member being adapted to project inwardly ofsaid rim through said concentric apertures, a brace extendingdiametrically of said rim substantially in the plane of said neck, theend of said brace remote from said neck being secured to said rim, thesecond end of said brace extending in juxtaposition to the inner end ofsaid member, and manually operable means connecting said member and the1 juxtaposed end of said brace simultaneously to effect an inward radialmovement of said ber to clamp said neck in xed angular relation to saidrim, and a relatively lesser movement of said brace to communicate forcediametrically il@ of said rim.

5. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck adapted to adjustably abut said rimin angular relation to the plane of the edge thereof, said neck having abore extending inwardly from said abutting end, means providing asurface contact betwen said rim and the abutting end of said neck, saidmeans having an aperture concentric with the aperture in said rim, a.member universally anchored in said bore and projecting externallythereof, said member being adapted to project inwardly of said rimthrough said concentric apertures, a brace extending diametrically ofsaid rim substantially in the plane of said neck, the end of said braceremote from said neck being secured to said rim, the second end of saidbrace extending in juxtaposition to the inner end of said member, andmanually operable means connecting said member and the juxtaposed end ofsaid brace simultaneously to eiect a clamping of said neck in fixedangular relation to said rim, and to communicate force diametrically ofsaid rim.

6. A stringed musical instrument comprising, incombination, a rim havingan aperture therein, a neck adapted to adjustably abut said rim inangular relation to the plane of the edge thereof, said neck having abore extending inwardly from said abutting end, means providing asurface contact between said rim and the abutting end of said neck, saidmeans having an aperture concentric With the aperture in said rim, amember universally anchored in said bere and projecting externallythereof, said member being adapted to project inwardly of said rimthrough said alined apertures, a brace extending diametrically o! saidrim substantially in the plane of said neck, the end of said braceremote from said neck being secured to said rim, the second end of saidbrace extending in juxtaposition to the inner end of said member, andmeans embracing said member and the juxtaposed end of said brace toeffect an inward radial movement of said member to clamp said neck inxed angular relation to said rim, and a corresponding movement of saidbrace to communicate force diametrically of said rim.

7. A stringed musical instrument comprising, in combination, a rim, aplate rigidly secured to the external peripheral surface thereof, saidrim and plate having alined concentric apertures, the outer face of saidplate being curved in a plane substantially perpendicular to the planeof said rim, a neck having a curved end adapted to abut the curved faceof said plate and an elongated longitudinal bore extending inwardlytherefrom, a member pivoted in said bore and projecting in- Wardly olsaid rim through said concentric apertures, a brace extendingdiametrically of said rim substantially in the plane of said neck andhaving one end secured to the periphery thereof, and means adapted toengage the inwardly projecting end of said member and the second end ofsaid brace to secure said neck in fixed angular relation to the plane ofsaid rim and to communicate a compressive stress to said brace.

8. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck having one end adapted adjustably toabut said rim in angular relation to the plane of the peripheral edgethereof, said neck having a bore extending inwardly from said abuttingend, means eiective to provide a surface contact between said rim andthe abutting end of said neck, said means having an aperture concentricwith the aperture in said rim, a member pivoted in said bore andprojecting inwardly of said rim thnough said concentric apertures. abrace extending diametrically of said rim substantially in plane of saidneck and having one end scoured to the periphery thereof, and meansadapted to engage the inwardly projecting end of said member and thesecond end oi said brace to secure said neck in fixed angular relationto the plane of said rim and to communicate a compressive stress to saidbrace.

9. A stringed musical instrument having, in combination, a rim having anaperture therein, a neck having one end adapted adjustably to abut saidrim in angular relation to the plane of the edge thereof, said neckhaving a bore extending inwardly from said abutting end, means providinga surface contact between said rim and the abutting end of said neck,said means having an aperture concentric with the aperture in said rim,a member having a pivotal and translating connection with said neckinwardly of said bore, said member projecting through said concentricapertures inwardly of said rim, a brace extending diametrically of saidrim and having one end anchored thereto at a point substantiallyopposite the point of attachment of said neck, and a single adjustablemeans effective to connect the second end of said brace to said rim andto clamp the abutting end of said neck in fixed angular relation to theplane of the peripheral edge of said rim. Y

10, In a stringed musical instrument, in combination with the body andneck, an adjustable mounting for the neck comprising coacting arcuateseats on the body and neck permitting angular adjustment relative tosaid body, and a clamp for connecting said neck to said body, said clampbeing pivotally and translatably connected to said neck intermediate itsrespective ends.

11. In a stringed musical instrument, in combination with the body andneck, an adjustable mounting for the neck comprising coasting arcuateseats on the body and neck to provide a bearing surface of substantiallyconstant area with the neck in angular adjustment relative to the body,and a clamp concealed within said neck for connecting said neck to saidbody, said clamp being pivotally connected to said neck intermediate itsrespective ends.

12. A neck for a stringed musical instrument of the type including aneck and body portion, said neck comprising an elongated member havingan end adapted to abut the body portion and a bore opening inwardly fromsaid end, and means mounted within said bore and projectingsubstantially longitudinally therefrom for engagement with said body,said neck being pivotally movable relative to said means about a pointintermediate its respective ends, and bodily movable relative to saidmeans in a plane substantially normal to its longitudinal axes.

13. A neck for a stringed musical instrument of the type including aneck and body portion, said neck comprising an elongated member havingan end adapted to transatably abut the bodyportion and a bore openinginwardly from said end and connecting means universally mounted withinsaid bore and projecting outwardly therefrom for engagement with saidbody, said neck being movable relative to said means about an axisremoved from said abutting end a relatively greater distance than is theclosed end of said bore.

14. A neck for a stringed musical instrument of the type including aneck and body portion, said neck comprising an elongated member havberhaving an end adapted to translatably and pivotally abut the bodyportion and a bore opening `inwardly from said end and means within lsaid bore and projecting outwardly therefrom for engagement with saidbody, said neck being movable pivotally relative to said means about anaxis normal to its longitudinal axis and translatable in a plane normalto the plane of the instrument.

15. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck having one end adapted to adjustablyabut said rim in angular relation to the plane of the edge thereof,means providing a surface contact between said rim and the abutting endoi' said neck, said means having an aperture concentric with theaperture in said rim, a universal connecting member anchored to saidneck adjacent its abutting end and projecting into the interior of saidrim through said concentric apertures, and means on said member adaptedto act against the inner peripheral wall of said rim adjustably toposition the abutting end of said neck in fixed bodily relation withsaid rim.

16. A stringed musical instrument comprising, in combination, a rimhaving an aperture therein, a neck having one end adapted adjustably toabut said rim in angular relation to the plane of the edge thereof, saidneck having a bore extending inwardly from said abutting end, meansproviding a surface contact between said rim and the abutting end oisaid neck, said means having an aperture concentric with the aperture insaid rim, a threaded member, one end of which is ivotally anchoredadjacent the inner end of said bore, the second end of which projectsthrough said concentric apertures into the interior oi said rim, and anadjustable nut on the inner end of said threaded member adapted to actagainst the inner peripheral wall of said rim to clamp said neck infixed angular relation with said rim.

17. A neck for a stringed musical instrument comprising an elongatedmember having one end adapted to abut the instrument, the other endextending outwardly therefrom, a member having a pivotal and translatoryconnection with said neck adjacent said abutting end, said memberprojecting from said neck for engagement with the instrument, saidneckbeing movable relative to said member about an axis removed fromabutting end a relatively greater distance than is said connection.

18. In combination with a stringed musical instrument having a rim and ahead supported on said rim, a neck comprising an elongated member havinga convex arcuate end adapted to abut said rim and an elongatedcylindrical bore eccentric of its longitudinal axis'and opening inwardlyfrom said arcuate end, means mounted within said bore to connect saidneck with said rim, and means to effect pivotal adjustment of said neckabout an axis perpendicular to the longitudinal axis of said bore andtranslating movement of said neck relative to said head.

'19. In combination with a stringed musical instrument having a rim anda head supported on said rim, a neck in movable abutment With said rim,connecting means to rigidly secure said neck in angular relation to saidhead and adjusting means adapted to permit translation of said necktoward and from the plane of said head.

20. In combination with a stringed musical instrument having a rim and ahead supported on said rim, a neck in movable abutment with said rim,connecting means to maintain said neck in iixed position relative tosaid rim and adjusting means adapted to permit bodily movement of saidneck normally of the plane of said head.

21. In combination with a stringed musical instrument of the classldescribed having a body and a head supported thereby, a neck adapted toabut said body and means to connect said neck to said body, saidconnecting means being adapted to permit pivotal movement of said neckabout an axis intermediate the ends thereof and translating movement ofsaid neck relative to the head of said instrument.

22. In combination with a stringed musical instrument of the classdescribed having a body comprising an annular rim, a head supported onsaid rim, and a neck adapted to abut said rim, connecting means adaptedto permit angular movement of said neck in planes normal to, andparallel with, the plane of said head, bracing means to reinforce saidrim and manipulative means operable to simultaneously adjust saidconnecting means and said brace.

23. A stringed musical instrument comprising, in combination, a rim, aneck having one end in abutment with said rim in adjustable angularlrelation to the plane of the peripheral edge thereof, means providing asurface contact between said rim and the abutting end of said neck in aplurality of angular positions of the latter, an adjustable braceextending diametrically of said rim, and a single manipulative adjustingmeans operable to stress said brace and to secure said neck in fixedangular adjustment.

24. A stringed musical instrument comprising, in combination, a rim, ahead supported thereby,

a neck having one end in adjustable abutment with said rim, anadjustable brace extending diametrically of said rim, means to effectbodily movement of the abutting end of said neck relative to the planeof said head and manipulative adjusting means operable to stress saidbrace and to secure said neck in fixed bodily position relative to saidhead.

25.' A stringed musical instrument comprising,

in combination, a' rim, a head supported thereby,

a neck having one end in abutment with said rim,

means to effect bodily movement of said neck relative to the plane ofsaid head and pivotal movement or". said neck about an axis parallel tothe plane of said head, an adjustable brace extending diametrically ofsaid rim, and a single

